Newyork subway

Whenever it rains hard, sewers clog with storm debris – the number of plastic garbage bags adrift in the world’s cities may truly exceed calculation – and the water, needing to go somewhere, plops down the nearest subway stairs. Add a nor’easter, and the surging Atlantic Ocean bangs against New York’s water table until, in places like Water Street in lower Manhattan or Yankee Stadium in the Bronx, it backs up right into the tunnels, shutting everything down until it subsides. Should the ocean continue to warm and rise even faster than the current inch per decade, at some point it simply wont subside. Schuber and Briffra (New York City Transit’s Superintendent of Hydraulics) have no idea what will happen then.

Add to all that the 1930s – vintage water mains that frequently burst, and the only thing that has kept New York from flooding already is the incessant vigilance of its subway crews and 753 pumps. Think about those pumps, New York’s subsay system, an engineering marvel in 1903, was laid underneath an already-existing, burgeoning city. As that city already had sewer lines, the only place for the subways to go was below them. “So,” explains Schuber, “we have no pump uphill.” In this, New York is not alone, cities like London , Moscow, and Washington built their subways for deeper, often to double as bomb shelters. Therein lies much potential disaster.

Shading his eyes with his white hard hat, Schuber peers down into a square pit beneath the Van Siclen Avenue station in Brooklyn, where each minute 650 gallons of natural groundwater gush from the bedrock. Gesturing over the roaring cascade, he indicated four submersible cast-iron pumps that take turns laboring against gravity to stay ahead. Such pumps run on electricity. When the power fails, things can get difficult very fast. Following the World Trade Center attack, an emergency pump train bearing a jumbo portable diesel generator pumped out 27 times the volume of Shea Stadium. Had the Hudson River actually burst through the Path train tunnels that connect New York’s subways to New Jersey, as was greatly feared, the pump train – and possibly much of the city – would simply have been overwhelmed.

In an abandoned city, there would be no one like Paul Schuber and Peter Briffa to race from station to flooded station whenever more than two inches of rain falls – as happens lately with disturbing frequency – sometimes snaking hoses up stairways to pump to a sewer down the street, sometimes navigating these tunnels in inflatable boats. With no people, there will also be no power. The pumps will go off, and stay off. “When this pump facility shuts down,’ says Schuber, “in half an hour water reaches a level where trains can’t pass anymore.”

Briffa removes his safety goggles and rubs his eyes. “A flood in one zone would push water into others. Within 36 hours, the whole thing could fill.”

Even if it weren’t raining, with subway pumps stilled, that would take no more than a couple of days, they estimate. At that point, water would start sluicing away soil under the pavement. Before long, streets start to crater. With no one unclogging sewers, some new watercourses form on the surface. Others appear suddenly as waterlogged subway ceilings collapse. Within 20 years, the water-soaked steel columns that support the street above the East Side’s 4, 5 and 6 trains corrode and buckle. As Lexington Avenue caves in, it becomes a river ~ Excerpt Pages 24 to 26 (from the Book THE WORLD WITHOUT US – Alan Weisman)